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Ecosystem PPT | Detailed Notes | Impacts
- 1. ECOSYSTEM • An ecosystemis a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms. 1
- 2. • The simplestdefinition of an ecosystem is that it is a community or group of living organisms that live in and interact with each other in a specific environment.
- 3. Ecosystem • An ecosystemcan be visualised as a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. Ecosystem varies greatly in size from a small pond to a large forest or a sea. Many ecologists regard the entire biosphere as a global ecosystem, as a composite of all local ecosystems on Earth. Since this system is too much big and complex to be studied at one time, it is convenient to divide it into two basic categories, namely the terrestrial and the aquatic. Forest, grassland and desert are some examples of terrestrial ecosystems; pond, lake, wetland, river and estuary are some examples of aquatic ecosystems. Crop fields and an aquarium may also be considered as
- 10. CONCEPT OF AN ECOSYST EM • Ecosystemshave been formed • on land and • in the sea by evolution that has created species to live together in a specific region. • Ecosystems have both non-living and living components that are typical to an area giving it its own special characteristics that are easily observed.
- 11. • An ecosystemis a structural and functional unit of ecology where the living organisms interact with each other and the surrounding environment. In other words, an ecosystem is a chain of interactions between organisms and their environment 11
- 12. CONCEPT OF ANECOSYSTEM •Definition of Ecosystem: The living community of plants and animals in any area together with the non-living components of the environment such as soil, air and water, constitute the ecosystem.
- 13. Concept of Ecosystem 13 There aremany supporting systems like Forests, oceans, grasslands, deserts which have structural components and functions. They all have living organisms interacting with their surroundings exchanging matter and energy. The word Ecology was coined by Earnest Haeckel in 1869 from Greek Words: Oikos (Home) + Logos(study) So ecology is study of organisms in their natural home interacting with the biotic and abiotic components (Surroundings)
- 14. What is Ecosystem??? • AnEcosystem is a self regulating group of biotic communities of species interacting with one another with their non-living environment exchanging energy and matter. • Therefore Ecology can be termed as--- “Study Of Ecosystems” 14
- 15. 15 • Ecosystem isa unit or a system which is composed of no. of sub-units • They may exchange energy & matter from outside – is an Open Ecosystem; or isolated from outside in a closed one. • The Closed once are generally artificial. Eg. Biosphere2, in Oracle, Arizona • Life on earth is sustained by the flow of energy from sun & cycling of nutrients Continue…..
- 16. CONCEPT OF ANECOSYSTEM • An ‘Ecosystem’ is a region with a specific and recognizable landscape form such as forest, grassland, desert, wetland or coastal area. • The nature of the ecosystem is based on its geographical features such as hills, mountains, plains, rivers, lakes, coastal areas or islands. • It is also controlled by climatic conditions such as the amount of sunlight, the temperature and the rainfall in the region. • The geographical, climatic and soil characteristics form its non- living (abiotic) component. • These features create conditions that support a community of plants and animals that evolution has produced to live in these specific conditions. • The living part of the ecosystem is referred to as its biotic component.
- 17. CONCEPT OF ANECOSYSTEM • Ecosystems are divided into • terrestrial or landbased ecosystems, and • aquatic ecosystems in water. • These form the two major habitat conditions for the Earth’s living organisms. • All the living organisms in an area live in communities of plants and animals. • They interact with their non-living environment, and with each other at different points in time for a large number of reasons.
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- 19. Characteristics of an Ecosystem •Structure of ecosystem • Biotic Structure • Abiotic Structure • Functions of Ecosystem • Trophic Structure • Food Chains • Food Web • Ecological Pyramids • Energy Flow • Nutrient Flow • Ecological Succession • Types of Ecosystems 19
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- 22. Biotic Components A) Producers-they produce their own food either by process of Photosynthesis or by Chemical Process • Plants produce food by Photosynthesis(using sun, CO2 and water) in presence of Chlorophyll. Thus they are also called as Autotrophs • There are some micro-organisms which produce organic matter to some extent by oxidation of certain chemicals in absence of sunlight. They are called as Chemosynthetic or Chemotrophs 22
- 23. Biotic Components 23 B) Consumers :Allorganisms which get their food by feeding on other organisms are called as Consumers • Herbivores- Feed on producers (plant eaters)also called as Primary Consumers • Carnivores- Feed on other consumers • If they feed on Herbivores- Secondary Consumers – eg frog • If they feed on Carnivores – tertiary Carnivores/ Consumers- eg. Snake, Big Fish • Omnivores- They feed on plants and animals- Man, many birds, fox • Detrivores- They feed on parts of dead organisms, wastes of living organisms. Also known as Saprotrophs or Detritus feeders
- 24. Biotic Components C) Decomposers They deriveenergy by breaking down complex organic matter to simpler once. E.g. Bacteria & Fungi 24
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- 26. Abiotic Components • They includevarious physical, chemical & Geographical factors; • Physical Factors: • The sunlight & shade • Intensity of Solar flux • Average Temperature • Annual Rainfall • Wind • Soil type, availability of water, We can clearly see the difference in solar flux, temp., rainfall pattern in desert , tropical & Tundra Ecosystem. While in grassland and forest they also vary as per geographical location 26
- 27. Abiotic Components 27 • They includeavailability of nutrients like Nitrogen, Phosphorus, Carbon, Hydrogen, potassium, Oxygen, sulphur, levels of toxic substances, salts causing salinity influence the function of ecosystem. Chemical Factors • Latitude, Longitude and altitude Geographical Factors
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- 29. 29 Nutrient Cycling &Energy Flow
- 30. Functions of Ecosystems:Trophic structure • In ecosystems energy and matter exchange occurs in a definite pattern. • Nutrients and energy move along food chain • Producers, consumers are arranged in a specific manner and their interaction along with population size is called as Trophic structure and the level as Trophic Level. • And the amount of living matter at each level is called Standing Crop or Standing Biomass 30
- 31. Food chain • Thesequence of eating and being eaten is known as food chain. • Someone is the food of other. • Two major food chains • Grazing- Starts from producers that is green plants – terrestrial, marine, pond ecosystem • Detritus- Starts with dead organic matter- Mangrove Ecosystem 31 This Photo by Unknown author is licensed under CC BY-SA-NC.
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- 33. 33 Grazing food chain TerrestrialFood Chain
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- 38. 38 Food web No foodchain is isolated. Organisms act at various levels in different food chains. Feed on more than one type of organism. Form a Complex Food Web. Thus, “Food Web - is a network of food chains where different types of organisms are connected at different trophic levels” so that there are a no. of options of eating and being eaten at each trophic level
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- 42. Significance: Food chainand Food Web 42 Energy and nutrient flow Maintain population of different species and thus maintain Ecological Balance Bio magnification: a rather harmful phenomenon. Eg: build up of DDT in higher animals. (Case Study- Pesticides - Diclofenac in Vultures.)
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- 44. Ecological Pyramids This Photo byUnknown author is licensed under CC BY-SA.
- 45. Ecological Pyramids 45 They are of3 Types: Pyramids of Numbers Pyramids of Biomass Pyramid of Energy or Pyramid of Productivity Starts with producers at the base and consumers at successive levels towards apex is called as an “Ecological Pyramid” Graphic representation of trophic structure and function of ecosystem
- 46. Ecological Pyramids • Graphic representationof trophic structure and function of ecosystem • Starts with producers at the base and consumers at successive levels towards apex is called as an “Ecological Pyramid” • They are of 3 Types: • Pyramids of Numbers • Pyramids of Biomass • Pyramid of Energy or Pyramid of Productivity 46
- 47. Pyramid of Number • Represents Numberof individual organism at each level. • May be Upright or Inverted. • Of Forest, grassland and parasitic food chain 47
- 48. 48 Upright – Grassland & Pond NarrowPyramid- Forest Inverted- Parasitic food Chain
- 49. Pyramid of Biomass Basedon total biomass i.e dry matter at every level in a food chain 49
- 50. Pyramid of Biomass • Basedon total biomass i.e dry matter at every level in a food chain • Biomass is the amount of living or organic matter present in an organism 50
- 51. Pyramid of Energy •Amount of energy at each trophic level. • Always Upright • Energy goes on reducing at each level. • Loss in the form of heat, respiration. • Shows sharp decline from producers to top carnivores. 51
- 52. Energy Flow • Energyflow in an ecosystem is Unidirectional • Source of energy is sun • Plants convert this energy into chemical energy • Energy is lost in body functions like respiration • Available passes to next trophic level • Follows two laws of thermodynamics • 1st Law: Energy can neither be created nor destroyed, it can be converted from one form to another • 2nd Law: energy dissipates as it is used. • Energy flow models: explain the flow of energy 52
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- 56. Major Ecosystems 56 Forest ecosystems Desert Ecosystems GrasslandEcosystems Aquatic Ecosystems
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- 58. 58 Forest Occupy roughly40 % of the land. The different components of forest ecosystem are as follows: • Abiotic Components: These are organic & inorganic substances present in the soil and atmosphere. In addition to minerals present in forest we find the dead organic debris, moreover light condition are different due to complex stratification in the plants. • Biotic Components: • Producers: These are mainly trees that show much species and greater degree of stratification. Besides trees there are also present shrubs, and ground vegetation. • Consumers: Primary Consumers: These are herbivores that include animals feeding on tree leaves, ants, beetles, grass hoppers, etc., and large elephants, deers, squirrels, etc.
- 59. 59 Continue.. • Secondary Consumers:These are carnivores, like snakes, birds, lizards, fox, etc. feeding on herbivores. • Tertiary consumers: These are top carnivores like lion tiger, etc. that eat carnivores of secondary level. • Decomposers: These are wide variety of micro organisms including, fungi, bacteria. • Also present are epiphytes, lianas • Extremely diverse and productive
- 60. 60 Layered structure • Emergentlayer • Canopy layer • Under storey • Shrub layer • Ground layer or forest floor
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- 62. 62 Desert occupy 17% of land. • Abiotic components include, light, temperature, minerals. • Biotic Components: • Producers : These are shrubs, especially bushes, some grasses, and few trees. E.g. Cacti, Xerophytes, mosses • Consumers: The most common animals are reptiles, and insects, there are some rodents, and birds, and above all ship of desert camels, feed on tender plants. • Decomposers: These are very few as due to poor vegetation the amount of dead organic matter is less. They are some fungi and bacteria.
- 63. Types 63 Tropical deserts: highheat, very dry Eg : Sahara, Thar desert Temperate desert: day temperatures very hot in summer and nights very cool in winter Eg: Mojave in Southern California Cold deserts: Cold winters and warm summers Eg : Gobi desert in China
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- 65. Grassland occupy comparativelyfewer area roughly 19 % of the earth’s surface. • Abiotic Components: These are nutrients present in soil, and aerial environment, thus the elements like, phosphates, sulphates, water, carbon dioxide, present in soil and in air. Moreover some trace elements are also present. • Biotic Components: • Producers: They are mainly grasses as species of Cynadon, Desmodium, besides them a few shrubs also contribute some primary production. 65
- 66. • Consumers: • PrimaryConsumers: The herbivores feeding on grasses are grazing animals, as cows, goats, rabbit, etc. besides them there are some insects as termites, millipedes that feed on grasses. • Secondary Consumers: These are carnivores feeding on herbivores these include, animals like, fox, jackals, snakes, frogs, birds. • Tertiary Consumers: Some times hawks, vultures, feeding on secondary consumer, thus occupy tertiary consumers. • Decomposers: The microbes active in the decay of dead organic matter of different form are fungi and some bacteria 66
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- 69. Pond Ecosystem • Producers areof following type • Macrophytes: these are large rooted plants, which include partly or completely submerged hydrophytes, e.g. : Hydrilla, Trapha, Typha. • Phytoplankton: These are minute floating or submerged lower plants e.g.: algae. • Consumers: They are heterotrophs which depends for their nutrition on the organic food manufactured by producers. 69
- 70. • Primary Consumers: •Benthos: These are animals associated with living plants , detrivores and some other microorganisms • Zooplanktons: These are chiefly rotifers, protozoans, they feed on phytoplankton • Secondary Consumers: They are the Carnivores which feed on herbivores, these are chiefly insect and fish, most insects & water beetles, they feed on zooplanktons. • Tertiary Consumers: These are some large fish as game fish, turtles, which feed on small fish and thus become tertiary consumers. • Decomposers: They are also known as micro-consumers. They decompose dead organic matter of both producers and animal to simple form. Thus they play an important role in the return of minerals again to the pond ecosystem, they are chiefly bacteria, & fungi. 70
- 71. 71 Lake Ecosystem • Bigfreshwater bodies with standing water • Planktons, Nektons, Neustons, Benthos, Periphytons • Stratification based on temperature differences
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- 74. 74 Ocean Ecosystems • OceanEcosystem are more stable than pond ecosystem, they occupy 70 % of the earth surface. • Abiotic Components: Dissolved oxygen, light, temperature, minerals. • Biotic Components: • Producers: These are autotrophs and are also known Primary producers. They are mainly, some microscopic algae (phyto- planktons) besides them there are mainly, seaweeds, as brown and red algae also contribute to primary production.
- 75. 75 • Consumers: Theyare all heterotrophic macro consumers • Primary Consumer: The herbivores, that feed on producers are shrimps, Molluscs, fish, etc. • Secondary Consumers: These are carnivores fish as Herring, Shad, Mackerel, feeding on herbivores. • Tertiary Consumers: These includes, other carnivores fishes like, Cod, Halibut, Sea Turtle, Sharks etc. • Decomposers: The microbes active in the decay of dead organic matter of producers, and animals are chiefly, bacteria and some fungi.
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- 78. 78 Estuarine ecosystems • Anestuary is a partially enclosed body of water along the coast where fresh water from river and streams meet and mix with salt water from oceans. This Ecosystems are considered as most fertile ecosystem. • Abiotic Components: Nutrients such as phosphorus and nitrogen, temperature, light, salinity, pH. • This ecosystem experience wide daily and seasonal fluctuations in temperature and Salinity level because of variation in freshwater in flow.
- 79. 79 • Biotic Components: •Producers: Phytoplankton's - these micro-organisms manufacture food by photosynthesis and absorb nutrients such as phosphorous and nitrogen, besides them, mangroves, sea grass, weeds, and salt marshes. • Consumers: Primary consumers, Zooplanktons that feed on Phytoplankton, besides them some small microorganisms that feed on producers. • Secondary Consumer: Include worms, shellfish, small fish, feeding on Zooplanktons • Tertiary Consumer : Fishes, turtles, crabs, starfishes feeding on secondary consumers. • Decomposers: Fungi & Bacteria are the chief microbes active in decay of dead organic matter.
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- 83. Ecosystem – CarbonCycle • Ecosystem – Carbon Cycle When you study the composition of living organisms, carbon constitutes 49 per cent of dry weight of organisms and is next only to water. If we look at the total quantity of global carbon, we find that 71 per cent carbon is found dissolved in oceans. This oceanic reservoir regulates the amount of carbon dioxide in the atmosphere (Figure 14.6). Do you know that the atmosphere only contains about 1per cent of total global carbon? Fossil fuel also represent a reservoir of carbon. Carbon cycling occurs through atmosphere, ocean and through living and dead organisms. According to one estimate 4 × 1013 kg of carbon is fixed annually in the biosphere through photosynthesis. A considerable amount of carbon returns to the atmosphere as CO2 through respiratory activities of the producers and consumers. Decomposers also contribute substantially to CO2 pool by their processing of waste materials and dead organic matter of land or oceans. Some amount of the fixed carbon is lost to sediments and removed from circulation. Burning of wood, forest fire and combustion of organic matter, fossil fuel, volcanic activity are additional sources for releasing CO2 in the atmosphere.
Editor's Notes
- #51 Oes on reducing at each eleve